A general cylindrical linear motor having a cylindrical field and an armature is shown in FIG. 12.
FIG. 12 is a side sectional view illustrating a configuration of the known cylindrical linear motor.
In FIG. 12, Reference Numeral 1 denotes a stator, Reference Numeral 2 denotes a mover, Reference Numeral 3 denotes a support mechanism, Reference Numeral 5 denotes a coil, Reference Numeral 6 denotes a permanent magnet, Reference Numeral 7 denotes a shaft support member, Reference Numeral 8 denotes a shaft, Reference Numeral 9 denotes a can, and Reference Numeral 12 denotes a yoke.
The stator 1 is configured in which the plurality of cylindrical coils 5 serving as electrical loading means are arranged along an axial direction on an inside of the yoke 12 formed of a magnetic substance. The mover 2 is configured in which the plurality of permanent magnets 6 serving as magnetic loading means are inserted and arranged along the axial direction on an inside of the can 9 extending in the axial direction. The support mechanism 3 is configured in which the shaft 8 is inserted and fixed into the permanent magnet 6 of the mover 2 and then the shaft 8 is allowed to pass through the shaft support member 7 of the stator 1.
FIG. 13 is a side sectional view illustrating a fixing mechanism for fixing the cylindrical linear motor shown in FIG. 12 to an external device.
In FIG. 13, Reference Numeral 13 denotes a frame, and Reference Numeral 14 denotes a tap hole.
To attach the stator 1 to the external device, the frame 13 is fitted to an outer periphery of the yoke 12, an end of the frame 13 is provided with the tap hole 14 having a female screw, and a bolt screw (not shown) is fitted to the tap hole 14, thereby fixing the linear motor to the external device (not shown).
FIG. 14 is a side sectional view illustrating a configuration in which a linear encoder is additionally attached to the known cylindrical linear motor. The stator 1 and the mover 2 have the same configuration as the configuration shown in FIGS. 12 and 13.
In FIG. 14, Reference Numeral 16 denotes a linear scale, Reference Numeral 17 denotes a detector, Reference Numeral 18 denotes a linear encoder, Reference Numeral 31 denotes a shaft support mechanism, Reference Numerals 71 and 72 denote ball spline nuts, and Reference Numeral 81 denotes a spline shaft.
The shaft support mechanism 31 includes the spline shaft 81 coupled to the mover 2, and the ball spline nuts 71 and 72 serving as shaft support members for supporting the shaft 8 in both ends of a metal pipe 4 of the stator 1 in the axial direction, thereby enabling to move the mover 2 in the axial direction.
The optical linear scale 16 of the linear encoder 18 is disposed at one end of the spline shaft 81 to which the mover 2 is attached, and the detector 17 for detecting the linear scale 16 is disposed on the stator 1 to face the linear scale 16. With such a configuration, a position of the mover 2 relative to the stator 1 in a sliding direction is detected by the encoder 18.
With such a configuration, when a current is allowed to flow from an external power supply (not shown) to the electrical loading means of the stator, a thrust force in the axial direction is generated between the electrical loading means of the mover and the magnetic loading means of the stator, the mover is supported to be movable in the axial direction through a gap of the stator by the support mechanism, and the thrust force is taken out by the shaft of the mover (e.g., see Patent Documents 1 and 2).
Patent Document 1: Japanese Unexamined Utility Model Registration Application Publication No. 6-62787 (see Page 2 of Specification, and FIGS. 1 to 4)
Patent Document 2: Japanese Unexamined Patent Application Publication No. 2000-4575 (see Page 9 of Specification, and FIGS. 5A to 5C)